| 摘要 |
<p>A current amplifier including two stages. A first stage is formed by a primary operational amplifier (IC1) connected in a virtual earth feedback configuration and having a feedback loop formed by a resistor (R1) and capacitor (C1) connected in parallel so that the primary operational amplifier has a frequency response up to a predetermined frequency and thereafter the frequency response rolls off at a predetermined rate. A second stage including another operational amplifier (IC2) connected in a virtual earth or non-inverting feedback configuration having a frequency characteristic chosen to provide in combination with the frequency characteristic of the primary amplifier a desired operating range for the amplifier. The predetermined frequency lies between the frequency extremes of the operating range and the frequency characteristic of the second stage has a constant gain up to said predetermined frequency and a gain matched with and complementary to the roll-off of the primary operational amplifier (IC1) above the predetermined frequency so that the overall frequency response of the current amplifier is flat over its operating range.</p> |
